1,720,954 research outputs found
Modeling floods in the Middle Zambezi Basin using remote sensing and hydrological modeling techniques.
No full textMbire District, in the Middle Zambezi Basin, experiences floods annually. The study aimed at applyingremote sensing and hydrodynamic modeling tools to map, and understand flood processes in order to improve flood management in the district. In determining the spatial and temporal variation of flood inundation in the district, NDVI MODIS images for the period 2005-2006, 2008-2009, 2013-2014 and 2014-2015 were processed in ILWIS GIS environment. The above period was classified by the Civil Protection Unit and ZINWA as flood years. Validation of the MODIS derived flood areas was done using 68 GCPs collected using participatory GIS mapping methods. A binary logistic regression modelthrough the SPSS software was used to determine the spatial variation of flood hazard as a function of environmental factors. The results were confirmed using hydrologic modeling techniques, where the HEC-HMS model helped to quantify the peak flow and runoff contributed by the three sub-basins in the Mbire District (Angwa, Musengezi and Lower Manyame). The HEC-RAS model was used to map inundated areas for the Lower Manyame Basin for the flood return periods, 10, 25, 50 and 100 years. Flood mapping using MODIS images showed that the maximum areas flooded is 1934km2 on 16 January 2006, and 1 895 km2 on 8 January 2015. A good agreement of (R2=0.86) between GCPs and MODIS derived flooded area for 8 January 2015 was recorded. Environmental factors that significantly explained flooding are distance from water bodies (p<0.05). Simulations through the HEC-HMS model indicated an average yearly observed flow rates of 15.6 * 107 m3 16.2 * 107 m3, and 25.7 * 107 m3 for Lower Manyame (Mapomha), Musengezi (C109) and Angwa (Angwa) basins respectively. These flows were against an average discharge of 19.7 * 107 m3/yr.,18.3 * 107 m3/yr. and 25.4 * 107 m3/yr. for Lower Manyame, Musengezi, and Angwa respectively. Model performance was evaluated and theefficiency for Musengezi showed a RMSE of 5.25 %, RBIAS of 0.04 % for Angwa the RMSE was 3.94 % and RBIAS of -0.003 % and Manyame gave a RMSE of 5.25 % and RBIAS of 0.07 %. The HEC-RAS simulated inundated areas are 56.3 km2, 57.3 km2, 58.4 km2, 58.7 km2, 59.1 km2 for the 2008-9 season, 10 year, 25 year, 50 year and 100 year return floods respectively and these are in and around Chikafa, Hunyani and Mushumbi Pools areas. The study concludes that Mbire District is vulnerable to floods hence the need for a flood protection measure framework that provides practical and feasible solutions, basic constructional guidelines for the protection of settlements and agricultural lands as well as a near real-time monitoring framework provided by this study.,WaterNe
Modeling Floods in the Middle Zambezi Basin using Remote Sensing and Hydrological Modeling Techniques
No full textMbire District, in the Middle Zambezi Basin, experiences floods annually. The study aimed at applying remote sensing and hydrodynamic modeling tools to map, and understand flood processes in order to improve flood management in the district. In determining the spatial and temporal variation of flood inundation in the district, NDVI MODIS images for the period 2005-2006, 2008-2009, 2013-2014 and 2014-2015 were processed in ILWIS GIS environment. The above period was classified by the Civil Protection Unit and ZINWA as flood years. Validation of the MODIS derived flood areas was done using 68 GCPs collected using participatory GIS mapping methods. A binary logistic regression model through the SPSS software was used to determine the spatial variation of flood hazard as a function of environmental factors. The results were confirmed using hydrologic modeling techniques, where the HEC-HMS model helped to quantify the peak flow and runoff contributed by the three sub-basins in the Mbire District (Angwa, Musengezi and Lower Manyame). The HEC-RAS model was used to map inundated areas for the Lower Manyame Basin for the flood return periods, 10, 25, 50 and 100 years. Flood mapping using MODIS images showed that the maximum areas flooded is 1 934 km2 on 16 January 2006, and 1 895 km2 on 8 January 2015. A good agreement of (R2=0.86) between GCPs and MODIS derived flooded area for 8 January 2015 was recorded. Environmental factors that significantly explained flooding are distance from water bodies (p<0.05). Simulations through the HEC-HMS model indicated an average yearly observed flow rates of 15.6 * 107 m3 16.2 * 107 m3, and 25.7 * 107 m3 for Lower Manyame (Mapomha), Musengezi (C109) and Angwa (Angwa) basins respectively. These flows were against an average discharge of 19.7 * 107 m3 /yr., 18.3 * 107 m3/yr. and 25.4 * 107 m3/yr. for Lower Manyame, Musengezi, and Angwa respectively. Model performance was evaluated and the efficiency for Musengezi showed a RMSE of 5.25 %, RBIAS of 0.04 % for Angwa the RMSE was 3.94 % and RBIAS of -0.003 % and Manyame gave a RMSE of 5.25 % and RBIAS of 0.07 %. The HEC-RAS simulated inundated areas are 56.3 km2, 57.3 km2, 58.4 km2, 58.7 km2, 59.1 km2 for the 2008-9 season, 10 year, 25 year, 50 year and 100 year return floods respectively and these are in and around Chikafa, Hunyani and Mushumbi Pools areas. The study concludes that Mbire District is vulnerable to floods hence the need for a flood protection measure framework that provides practical and feasible solutions, basic constructional guidelines for the protection of settlements and agricultural lands as well as a near real-time monitoring framework provided by this study
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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